HRM Wallstar Oil Boiler - Advice please

[SJB060685]

From what I've seen, heard and read I'm still leaning towards a pump issue. I'm not saying it is but it's what I'd run a couple tests on first. To prove or disprove ignition and atomization things have to be done but I'm not going to say what. It could be air related as well but I'm not convinced.
I cant say anymore, from here on in it needs a decent engineer with good experience and the right gear.

 

[SimonG]

Have you taken the burner out before?

If you have, take it out and take a picture looking down the blast tube. Make sure you unplug coil or turn it all off.

 

[Simonvr46]

From what I've seen, heard and read I'm still leaning towards a pump issue. I'm not saying it is but it's what I'd run a couple tests on first. To prove or disprove ignition and atomization things have to be done but I'm not going to say what. It could be air related as well but I'm not convinced.
I cant say anymore, from here on in it needs a decent engineer with good experience and the right gear.

Ok no probs, thank you for your help.
Going to give someone local a ring tomorrow for advice before getting them to come visit.
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Have you taken the burner out before?

If you have, take it out and take a picture looking down the blast tube. Make sure you unplug coil or turn it all off.

No never taken burner out before. Although I work as a mechanical fitter im not confident with taking burner apart.

 

[SimonG]

No problem, respect somebody who knows there limits.

Was the nozzle changed at the last service?

Whereabouts in the country are you?

 

[SJB060685]

By all means update us if you get a result.

 

[Simonvr46]

No problem, respect somebody who knows there limits.

Was the nozzle changed at the last service?

Whereabouts in the country are you?

Will give most things ago but know when I’m at my limits lol.
Yeah nozzle and filters was changed last service.
Im in Lincolnshire.

 

[SimonG]

Too far for me. Hope you find somebody to sort it and please let us know what the problem was.

 

[Simonvr46]

By all means update us if you get a result.

Yeah sure will. Hopefully if I get sorted I’ll be able to pass on my fix to someone else.
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Too far for me. Hope you find somebody to sort it and please let us know what the problem was.

Bacon, sausage and egg butty???

 

[Best]

Fool the photocell into seeing light once burner fires and see if burner continues to fire while photocell out. Handy on Sterling burners.
That will prove flame is poor for some reason or photocell had obstructed view.
Does sound like flame burn is barely making it

 

[Simonvr46]

Fool the photocell into seeing light once burner fires and see if burner continues to fire while photocell out. Handy on Sterling burners.
That will prove flame is poor for some reason or photocell had obstructed view.
Does sound like flame burn is barely making it

Boiler started up 1st attempt this morning.......

I did try this awhile ago. I think when I removed photocell burner continued running but when I covered photocell it shutdown if my memory serves me correctly.
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Took burner unit off and had a look. I’ve attached photos. Tip of nozzle is damp with oil.
Any suggestions?

 

[Best]

Boiler started up 1st attempt this morning...

I did try this awhile ago. I think when I removed photocell burner continued running but when I covered photocell it shutdown if my memory serves me correctly.

Combustion is most likely then poor if flame isn’t partly being obscured from photocell view.
But can have one of many causes.
Nozzle could be faulty, or air setting wrong or burner drawing in flue gases, or oil pump pressure is set wrong, are some possibilities.

 

[SimonG]

Nozzle being damp is fine. Dont like the position of the electrodes though.

 

[Simonvr46]

Nozzle being damp is fine. Dont like the position of the electrodes though.

Just a quick question, the capscrew that is in the main body of the burner just below the black plastic cover for the photo cell etc is that what is undone when boiler serviced? If so should the gasket be replaced?
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could the electrode be causing the issue of lockout? If it’s not positioned correctly could the photocell fail to detect it sometimes?

is the blast tube ok or should that be cleaner?

 

[SJB060685]

The Alan key under the black cover is used to undo and remove the burner, you've detached the whole thing. The electrodes don't look right in terms of position and could be part of the reason it doesn't light sometimes, it doesn't explain why it sometimes ignites and then loses flame during 5 second safety time though.

 

[Simonvr46]

The Alan key under the black cover is used to undo and remove the burner, you've detached the whole thing. The electrodes don't look right in terms of position and could be part of the reason it doesn't light sometimes, it doesn't explain why it sometimes ignites and then loses flame during 5 second safety time though.

That capscrew is seriously tight, should the gasket be replaced when burner is split?

wish id paid more attention to what he was doing when he serviced it.
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I’ve contacted a 3 local heating engineers, 1 said he would go with pump bring issue. 1 said possibly pump but wouldn’t be sure and the other said it’s the control box.

 

[SJB060685]

That capscrew is seriously tight, should the gasket be replaced when burner is split?

wish id paid more attention to what he was doing when he serviced it.
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I’ve contacted a 3 local heating engineers, 1 said he would go with pump bring issue. 1 said possibly pump but wouldn’t be sure and the other said it’s the control box.

When you split the burner any gaskets need to be replaced if not In good reusable condition. I've not experienced on this burner but have on a Riello where the seal had perished causing it to draw more air which was extinguishing the flame like you're experiencing at times.
I did not say for sure it was the pump, only suspicious and I based that on what I've seen heard and read, like I said I cant be sure without checking a couple things. Control box can cause this issue yes and the DKO does things slightly different in lockout mode but again it's hard to say without being there.

 

[Simonvr46]

As far as I’m aware the only parts that have been replaced during service are the filter and the nozzle, no mention of replacing gasket.

should that capscrew be stupidly tight to undo?

with regards to blast tube does that look in good condition?

 

[SJB060685]

Image from manual to show the long bolt you should be removing. Blast tube looked ok, usual wear and tear but overall in acceptable condition. Couldn’t see if there were any obstructions to the cell though

 

[Simonvr46]

View attachment 42435

Image from manual to show the long bolt you should be removing. Blast tube looked ok, usual wear and tear but overall in acceptable condition. Couldn’t see if there were any obstructions to the cell though

Found that image in the HRM handbook. Just didn’t know about how tight that screw should be? Used to screws and bolts having torque setting on them lol.

 

[SJB060685]

These things do quite often have torque settings yes. Alan key below on burner casing looks like the one going by image. Been a while for me on this burner lol

 

[Best]

The large Allen bolt is used for to split the burner (main part from part that also has blast tube and flange on it.
Removing the entire burner is fine if you make sure the seal at flange to boiler is still okay and the bolts are holding burner in firm.
No need to over tighten

 

[Simonvr46]

Found paper work from when it was last serviced, all the last few service record sheets I found all day pump pressure of 120psi even when it was serviced by a different company.

 

[SJB060685]

When was this last record dated? Smoke level fine, CO2 is about right depending on when it was serviced, excess air maybe a little too high. Pump pressure is looking good from my calculations.

 

[Simonvr46]

When was this last record dated? Smoke level fine, CO2 is about right depending on when it was serviced, excess air maybe a little too high. Pump pressure is looking good from my calculations.

That was July 2019 that it was serviced.
How is excess air reduced?

 

[Best]

Looks good readings to me, but I never just assume they are accurate or honest and do my own test results

 

[Best]

That was July 2019 that it was serviced.
How is excess air reduced?

Adjusting the air is for your oil service person to do using an analyser.
I would say excess air is fine. The CO2 reading is good and reducing the air will begin to increase the CO2.
You tried putting your hand partly over air intake and it didn’t help, so leave air settings untouched.

 

[SJB060685]

This needs to be done in conjunction with a FGA (flue gas analyser) and I shouldn’t tell you because randomly adjusting can through all other readings out. Ideally you want maximum combustion and CO2 with no excess air, this however is not practical in the modern world and you will always have a lower CO2 and certain amount of excess air, this is down to the fact increasing CO2 also increases smoke and soot emissions. Again CO2 is set depending on ambient air temperature and density. If excess air was too high it can force heat up through the flue and reduce efficiency, it can also cool the combustion process and increase CO ppm as well as extinguish flame, the data sheet suggests your efficiency and CO are good, certainly for a non condensing boiler.

 

[Simonvr46]

This needs to be done in conjunction with a FGA (flue gas analyser) and I shouldn’t tell you because randomly adjusting can through all other readings out. Ideally you want maximum combustion and CO2 with no excess air, this however is not practical in the modern world and you will always have a lower CO2 and certain amount of excess air, this is down to the fact increasing CO2 also increases smoke and soot emissions. Again CO2 is set depending on ambient air temperature and density. If excess air was too high it can force heat up through the flue and reduce efficiency, it can also cool the combustion process and increase CO ppm as well as extinguish flame, the data sheet suggests your efficiency and CO are good, certainly for a non condensing boiler.

Thanks for that, I’ve no intention of adjusting settings I’ll leave that to experts with correct equipment.
2 Questions

1 - Would the excess air cause the burner to lockout?
2 - Could excess be caused if that gasket hasn’t been replaced?

 

[SJB060685]

Like I said I have known flames to extinguish due to faulty gaskets/seals, however I would expect it to happen constantly if these were a problem.
If there was a problem with gaskets/seals causing an excess of air but not enough to extinguish flame then I would expect to see other readings on my FGA out and the sheet you showed me looked like very good figures (providing they are similar now). I did say the excess air was a bit high yes but only a little to what one usually would see.

 

[Simonvr46]

Like I said I have known flames to extinguish due to faulty gaskets/seals, however I would expect it to happen constantly if these were a problem.
If there was a problem with gaskets/seals causing an excess of air but not enough to extinguish flame then I would expect to see other readings on my FGA out and the sheet you showed me looked like very good figures (providing they are similar now). I did say the excess air was a bit high yes but only a little to what one usually would see.

Figures have been very similar on last few service record sheets, although the 1 from 2016 doesn’t show excess air.
Think I’ll give the electrode gap a check sometime this week.

 

[SJB060685]

Above is a screen shot of what the electrode dimensions should be. Also note the burner head dimensions of 3-5mm. Like I said I haven’t touched a sterling burner in some time so would have to re familiarise myself. The Alan key you were turning under black cover might be the adjuster for nozzle assembly position, again I can’t remember off the top of my head so apologise if it’s not. Both are extremely important to ensure safe and non delayed ignition.
Check those out if you feel compelled but the rest leave to the engineer, I know you have a background in engineering and more importantly that you know your limits. The attending engineer should take the time to check everything.

 

[Simonvr46]

View attachment 42437

Above is a screen shot of what the electrode dimensions should be. Also note the burner head dimensions of 3-5mm. Like I said I haven’t touched a sterling burner in some time so would have to re familiarise myself. The Alan key you were turning under black cover might be the adjuster for nozzle assembly position, again I can’t remember off the top of my head so apologise if it’s not. Both are extremely important to ensure safe and non delayed ignition.
Check those out if you feel compelled but the rest leave to the engineer, I know you have a background in engineering and more importantly that you know your limits. The attending engineer should take the time to check everything.

Cheers mate, much appreciated with your help and guidance. Best hunt out my feelers to check gap. Must remember to disconnect boiler from power supply, don’t want boiler starting up while I’m checking electrodes lol.

 

[SJB060685]

Cheers mate, much appreciated with your help and guidance. Best hunt out my feelers to check gap. Must remember to disconnect boiler from power supply, don’t want boiler starting up while I’m checking electrodes lol.

Yes isolate power to system at switched fused spur and shut oil off, take solenoid off as well if really worried. Didn’t say this because it’s obvious lol.
Like I said whoever attends needs to check everything from start to finish, explain to the engineer that sometimes it starts and you lose flame during safety time then lock out and other times it won’t even start, tell them what parts have already been replaced randomly (which is not a sign of a good engineer) and hopefully they’ll get to the bottom of it. From the video I took pre purge, ignition, then loss of flame, cell senses that, I heard the solenoid close and then thermomechanical switch cause lockout. However that doesn’t explain why sometimes it won’t even start, so couple issues might be found.

 

[Simonvr46]

Yes isolate power to system at switched fused spur and shut oil off, take solenoid off as well if really worried. Didn’t say this because it’s obvious lol.
Like I said whoever attends needs to check everything from start to finish, explain to the engineer that sometimes it starts and you lose flame during safety time then lock out and other times it won’t even start, tell them what parts have already been replaced randomly (which is not a sign of a good engineer) and hopefully they’ll get to the bottom of it. From the video I took pre purge, ignition, then loss of flame, cell senses that, I heard the solenoid close and then thermomechanical switch cause lockout. However that doesn’t explain why sometimes it won’t even start, so couple issues might be found.

Who ever I get to come look at boiler I’ll be keeping closer eye on, I think after chatting to you guys on here with the advice you have all given me I think I have a decent understanding on how it all works and what to look for.
I’ll have look at electrodes 1st then get someone to look at it.

 

[Simonvr46]

Adjusting the air is for your oil service person to do using an analyser.
I would say excess air is fine. The CO2 reading is good and reducing the air will begin to increase the CO2.
You tried putting your hand partly over air intake and it didn’t help, so leave air settings untouched.

Hiya,
Ive no intention of adjusting any settings as although the burner is pain in backside sometimes, the majority of time it’s ok so I’d rather it be like that until it’s sorted out properly.
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View attachment 42437

Above is a screen shot of what the electrode dimensions should be. Also note the burner head dimensions of 3-5mm. Like I said I haven’t touched a sterling burner in some time so would have to re familiarise myself. The Alan key you were turning under black cover might be the adjuster for nozzle assembly position, again I can’t remember off the top of my head so apologise if it’s not. Both are extremely important to ensure safe and non delayed ignition.
Check those out if you feel compelled but the rest leave to the engineer, I know you have a background in engineering and more importantly that you know your limits. The attending engineer should take the time to check everything.

I had chance today when I got home from work to check electrodes. I unhooked burner unit like I had the other day and got my trusty set of feelers out. The electrodes appear to be within the specified tolerance of the the screenshot page.
I did take blast tube off and give the fins at the nozzle end a good clean, I’m assuming the fin that has corner bent over is for the photocell to detect flame? I made sure it was clean.
Also had quick look at the pump, took cover off and then undid the 3 Allen head screws, pump gears looked clean, couldn’t see anything obvious. Without fully stripping pump down and measuring components it’s hard to tell if parts are worn. Once bled air out of pump it started up 1st time.
I’ve been quoted about £125 + vat to have new pump fitted.

 

[SJB060685]

Yes there should be no obstruction so the cell can detect light, if there was the burner would ignite then go to lock out due to no flame sensing.
I mentioned the pump gear set, drive key and coupling but did not say have a look yourself lol. I know you have a back ground in engineering but I only ever opened up a pump if I had spare seals and pump at hand and after I was confident there was a problem with it. What was the drive key and pump coupling like? These pumps should all be put back together with a certain torque as we discussed above.

 

[Simonvr46]

Combustion is most likely then poor if flame isn’t partly being obscured from photocell view.
But can have one of many causes.
Nozzle could be faulty, or air setting wrong or burner drawing in flue gases, or oil pump pressure is set wrong, are some possibilities.

Current heating engineer has replaced nozzle at every service.

Pump pressure recored at the last service in 2019 was same as service in 2016 by different company and is correct to what the specification of burner

How would the burner draw in flue gases? Wouldn’t that be picked up on flue gas analysis?

If air setting was wrong wouldn’t that affect co and flue temp etc?
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Yes there should be no obstruction so the cell can detect light, if there was the burner would ignite then go to lock out due to no flame sensing.
I mentioned the pump gear set, drive key and coupling but did not say have a look yourself lol. I know you have a back ground in engineering but I only ever opened up a pump if I had spare seals and pump at hand and after I was confident there was a problem with it. What was the drive key and pump coupling like? These pumps should all be put back together with a certain torque as we discussed above.

From what I could see and feel, there was a bit of play in the gear wheel against the drive key but without knowing what is acceptable it’s hard to judge.

Had the seal on the external case needed replacing I have numerous o rings and could have temp fixed. The main body of pump is metal on metal so gave it a clean prior to reassembly.

I found data sheet for the Danfoss BFP11 pump and no torque settings shown on it, so a gentle nip or as we call it a British Standard Nip.

 

[SJB060685]

I cant remember the correct torque setting, I'm sure I saw it on a danfoss bfp pump YouTube video.
The drive key should be solid in its groove with no play, if there was it could cause your issue and eventually shear completely and you would have no pressure or ignition. A photo would of been nice but I'm not suggesting open up again. A dodgy pump coupling could also cause the same.

The burner could draw in flue gases if the flue seals had failed or burner flange gasket was faulty, or anywhere else that could allow products of combustion to escape inside the casing. You could detect these products with a FGA yes.

Just out of curiosity have you ever dipped the tank for traces of water with detection paste? I'm sure this isn't the problem due to what I've seen but thought I'd ask.

With regards to the quote for changing the pump I'm not so sure if that will help now based on what you've said today but without seeing the gear set, drive key or coupling I cant say for sure.

 

[Simonvr46]

I cant remember the correct torque setting, I'm sure I saw it on a danfoss bfp pump YouTube video.
The drive key should be solid in its groove with no play, if there was it could cause your issue and eventually shear completely and you would have no pressure or ignition. A photo would of been nice but I'm not suggesting open up again. A dodgy pump coupling could also cause the same.

The burner could draw in flue gases if the flue seals had failed or burner flange gasket was faulty, or anywhere else that could allow products of combustion to escape inside the casing. You could detect these products with a FGA yes.

Just out of curiosity have you ever dipped the tank for traces of water with detection paste? I'm sure this isn't the problem due to what I've seen but thought I'd ask.

With regards to the quote for changing the pump I'm not so sure if that will help now based on what you've said today but without seeing the gear set, drive key or coupling I cant say for sure.

I would have hoped current heating engineering would recognise fault if flue gases was being drawn back in.

I’ll have another look at the pump sometime this week and take photo. Im not sure if it was the shaft rotating of if it was the gear wheel on the drive key/ drive key in shaft.
I know when we had new oil tank in 2017 there was no mention of water in the oil when the existing oil was pumped out, also the pump showed no signs of water being sucked through.

 

[SJB060685]

If there was emulsified oil you would have seen a white gooey paste like substance. I was almost certain this wasnt the case but thought I'd ask.

 

[Simonvr46]

I cant remember the correct torque setting, I'm sure I saw it on a danfoss bfp pump YouTube video.
The drive key should be solid in its groove with no play, if there was it could cause your issue and eventually shear completely and you would have no pressure or ignition. A photo would of been nice but I'm not suggesting open up again. A dodgy pump coupling could also cause the same.

The burner could draw in flue gases if the flue seals had failed or burner flange gasket was faulty, or anywhere else that could allow products of combustion to escape inside the casing. You could detect these products with a FGA yes.

Just out of curiosity have you ever dipped the tank for traces of water with detection paste? I'm sure this isn't the problem due to what I've seen but thought I'd ask.

With regards to the quote for changing the pump I'm not so sure if that will help now based on what you've said today but without seeing the gear set, drive key or coupling I cant say for sure.

Your correct about the YouTube video, 5Nm for external Allen screws and 3Nm for the 3 internal screws.

 

[SJB060685]

Your correct about the YouTube video, 5Nm for external Allen screws and 3Nm for the 3 internal screws.

There you go, I knew I had seen it somewhere

 

[Simonvr46]

New heating engineer came and replaced the pump, after speaking to Danfoss they recommended fitting BFP21L3 instead of the BFP11L3, heating engineer set pump pressure at 120psi and used FGA to set burner up. All running spot on.
Next morning burner locked out.
Heating engineer been back and resealed all the joints in pipe work with oil seal.
Burner still locking out, but starting after reset.

This evening boiler won’t start.....

Could it be electrodes??

 

[SJB060685]

Remind me again what parts have been replaced?

 

[Simonvr46]

Remind me again what parts have been replaced?

Transformer, pump, capacitor, nrv/firevalve, photocell, solenoid and the control box (7years ago its now a dko).

 

[SJB060685]

Christ that's virtually everything. Yes if the electrode gap is wrong or dirty electrodes it could fail to ignite. If it was arching elsewhere other than at electrode ends then the photocell will usually detect false light and not even open the solenoid for ignition and go straight to lockout. Has this been checked? When the pump was replaced was the coupling checked and/or replaced? You could still be experiencing an excess of air at times if seals were perished as we've discussed before. I have a feeling you might have more than one issue still but of course I could be wrong.

 

[Simonvr46]

Christ that's virtually everything. Yes if the electrode gap is wrong or dirty electrodes it could fail to ignite. If it was arching elsewhere other than at electrode ends then the photocell will usually detect false light and not even open the solenoid for ignition and go straight to lockout. Has this been checked? When the pump was replaced was the coupling checked and/or replaced? You could still be experiencing an excess of air at times if seals were perished as we've discussed before. I have a feeling you might have more than one issue still but of course I could be wrong.

Yeah not much left to replace, the coupling was replaced with new pump.
New engineer says that the excess air amount that’s registering on FGA is ok.
He looked at electrodes when he had burner apart and said they look ok, couldn’t see any sign of arcing other than where should be.

 

[SJB060685]

Has he checked thoroughly though rather than just saying it looks ok? Someone I know had this recently where it was only intermittently arching elsewhere. You got fuel, you got new pump and coupling I know what I'd be looking at next.

 

[Simonvr46]

Im going to speak to him tomorrow, see what he suggests and I’ll enquire about the electrodes.

 

[SJB060685]

When it doesn't start at all do you hear the solenoid click?